Semi-shift invariant operations for optical computing

Semi-shift invariant operations for optical computing

Détails concernant le projet

Coût total:

Non disponible

Contribution de l'UE:

Non disponible

Coordonné à/au(x)/en:

France

Sujet(s):

Régime de financement:

CSC - Cost-sharing contracts

Objectif

- In this work, the potential performance of free space optoelectronic systems, implementing massively parallel semi-shift-invariant operations on two-dimensional data, will be evaluated. The evaluation process will include a theoretical study and the construction and experimental evaluation of key elements and a demonstration system or systems. The systems investigated combine "replication" of an input pattern, reconfigurable linear filtering and application of point-non-linearities. The replication is done optically, preferably with incoherent light, using a device such as a special diffractive element or a lenslet array. The filtering is done by masks whose transparency functions control their operation;- The research will mostly target the following two computing paradigms :- multichannel correlator;- cellular machines.- During the first and second years, the main thrust of the research was on miniaturising optical shift-invariant and semi-shift-invariant (convolvers/correlators) optical systems, and on developing suitable optical computing architectures to exploit them. On the optical side, both substrate mode optics and the LAHC (Lenslet Array Holographic Convolver) were investigated. In particular, a feasibility demonstrator for the LAHC was constructed, and several variations of the LAHC were introduced and analysed. On the systems/architecture side, a processing paradigm based on optical simulated annealing, combining optical semi-shift-invariant interconnections, an optical "Boltsman machine", and smart-pixels devices is being investigated, both in theory and through experiments with conventional correlators.- Design of optical architectures Preceding intensive investigation of any specific architecture, a theoretical comparison of alternative implementation schemes for both architectures (multichannel correlator and cellular machine) will allow selection of the best configurations. The simplicity of the optical configuration and its suitability for practical application will be especially taken into account. This study appears easier for the correlator case; the design of the cellular machine requires an accurate literature review. This study may lead to the design of original approaches.

- Theoretical study of the performance of selected configuration candidates After the preliminary overview, detailed analysis of the performance capabilities of each approach will be used to select the best configuration for each of the two systems. As described in the previous paragraph, diffraction, aberrations, mechanical precision, and other related parameters will be investigated in depth. This analysis will include both theoretical (paper and pencil) and computer simulation.

- Evaluation of suitable filters for the correlator An intuitive approach will allow design of adequate filters for recognition of multiple objects (possibly some road signs as a test case) giving relevant features for the post-processing stage.

- Experimental demonstration of the two selected implementations The demonstration will show the practical feasibility and verify results from the analysis part of this work. This will include :

Multichannel correlator :- use of an SLM for the input object;- design of the non-reprogrammable, gray-scale masks;- image replication;- detection and display of the correlation output with a suitable optoelectronic and electronic system. As a rough estimate, it is expected that about 100 channels, each with 100 x 100 resolvable pixels will be feasible for this demonstration.

Cellular machines :- LED array, or a binary SLM device, will simulate the dilute emitters associated with the Pes;- image replicator (diffractive or lenslet-array-based) device will implement the neighbour interconnects;- non-reprogrammable (fixed) mask for neighbour selection;- integrated optoelectronic detector array (possibly a photodiode array) and electronic to simulate detection and thresholding. Here, the feedback shall be electronic. The use of an LCLV for this function will be considered;- a rough value of 100 Pes, each interconnected with a neighbourhood of 25, is expected to be feasible for this demonstration.